If you mean "dressing" as in stuffing, just add some cranberries to a recipe you already use.
If you mean a cranberry sauce, the easiest is on the package - one bag (12 oz), 1c water, 1c sugar, boil together and that's it. You can also add orange zest, or sub orange juice for some of the water, or add other herbs and spices you like.
Many recipes available for both...search here under Recipes, or elsewhere on web.